1. Bonnell coil - the coil system used primarily in budget bedding. It is laced with a helical wire across the bed. The coils have a distinct hour glass shape and there are usually minimal coils in the bed. This system is still in 70% of the beds in homes today.
2. Continuous coil - a coil system produced with one continuous piece of steel. Used in serta and kingsdown mattresses. It is a firmer feel; due to most of the steel being on the surface of the unit. This system is not a very flexible and body conforming system.
3. Pocketed coil - also known as the marshall coil unit, designed in 1927 by james marshall. Simmons is the primary user of this style of coil. Other vendors, spring air and kingsdown, use a similar coil in some of their beds. It has the distinction of being the only coil system that does not use helical lacing. All of the coils work independently of one another, thus giving it better conformability, and less motion transfer.
4. Offset coil - coil system with a slight hour glass shape, the system is usually attached with a border wire and helical lacing. It is similar to the bonnell coil, except the top and bottom of the coil have flat, straight sides to allow for better hinging action. Common in sealy posturpedics.
Coil system components
1. Helical lacing - an elongated coil wire where all turns are of consistent, tiny diameter used to join individual coils to each other and to the boarder rod. Similar to the “lacing” on your shoes.
2. Border rod - a thick steel rod that runs around the edge of the coil system. It helps to hold the coil system together and create edge reinforcement. Most budget bedding has a border rod.
3. Foam encased - using foam around the perimeter of the bed for edge support, which is usually considered an upgrade from a border rod.
4. Coil turns - the number of circles in a coil.
5. Working turns - the number of coil turns that actually move up and down to give support.
6. Tempered - heat treatment of wire to reduce brittleness and set the shape (memory) of a coil. This is accomplished by an electric charge, oven heating or both.
7. Hinged - some mattresses that have border rods are hinged so that you can bend them around corners to get them into a room.
8. Gauge - the thickness of steel is measured by gauges. Gauge is measured by how many pieces of steel make an inch when stacked on top of one another. The thicker the steel the lower number of the gauge. (15 gauge = the amount of wires (15) stacked on top of each other to equal one inch of material.)
9. Torsion bars - a type of formed wire spring system used in foundations instead of coils. It is used primarily in box springs.
1. Insulator - the first layer next to the innerspring. It forms a barrier between the softer foam layers to keep them from pocketing or getting pushed into the coil unit.
2. Middle upholstery - adds cushioning and support to the mattress.
3. Quilt - this is the top layer of foam and ticking sewn together to hold the stitching and is surrounded by the tape edge.
4. Tape edge - the banding around the mattress that finishes it off and joins the sides to the top.
5. Ticking - the upholstery on the top and sides of the mattress. It can be made of many different fabrics depending on the quality and price of the mattress. Belgium damask, terry cloth, micro fiber etc.
1. Latex - natural foam made of rubber. It is the softest of all foams used in beds today. The best latex is called talalay. Talalay is a process that takes 230 impurities out of the rubber before it becomes latex and makes it hypoallergenic, consistent, and highly durable.
2. Infinilux - a synthetic form of latex. It feels very similar to latex, but is less expensive to produce.
3. Visco elastic - sometimes referred to as memory foam, nasa foam or swedish foam. It is also a highly durable foam that has somewhat of a more dense, firmer feel than latex. The greater the density, the more durable the foam is. This foam is also heat sensitive, and is more pliable the warmer that it becomes.
4. Convoluted - sometimes called egg crate foam, it has hills and valleys the help to ease pressure points. It was invented to help burn victims rebuild tissue by promoting good circulation.
1. Box spring - any foundation that works on coil on coil construction. This type of foundation still has a full flex motion. Most companies have gotten away from full motion as it does not give great over all support.
2. Semi flex foundation - a foundation that uses torsion bars, these are made from heavy gauge steel and provide a stable and ridged structure.
3. Solid state - also called a build up or a platform foundation; this is a promotional type of foundation. This is a wooden box with a cover on it. It is usually used in inexpensive sets or tempurpedic.
4. Low pro box - this can be any of the above foundations; it is just a smaller height and should do the same work as the taller ones. Usually it is about three inches lower.